Exercise 9.1 - Fluorescent Analysis of Microtubules

LEVEL I

Figure 9.1 Macrophage stained with FITC labeled anti-tubulin

Materials

• Projection slides of tubulin fluorescence1

Procedure

1. Draw the cells represented in Figure 9.1. These are photographs of macrophages treated with a fluorescent anti-tubulin antibody.

2. Describe the shape and general appearance of the cells observed in the first three slides. How does the organization of the microtubules affect cell shape?

3. Identify a place in the cell from which the microtubules appear to extend. This is the microtubule-organizing center. Label it in the appropriate drawings.

4. The cells in slide 4 were exposed to colchicine for 30 minutes and then prepared as above. What do you predict will happen to the microtubules after cell treatment with colchicine? Was this prediction fulfilled? Draw a colchicine-treated cell.

5. The cells in slide 5 were placed on ice for 30 minutes and then prepared as above. What do you predict will happen to the microtubules after incubation of the cells in the cold? Is the microtubule diameter larger or smaller than the resolving power of the light microscope? How can microtubules be visualized with immunofluorescence if the tubules are less than the resolution of the light microscope?